1. Field of the Invention
The invention generally relates to an elecrographic recording device in which a gaseous discharge is produced by means of a multi-pin electrode assembly, so that the thus obtained charged particles, are disposed on a record medium to make a record of information thereon. More particularly, the present invention relates to interconnection means between record electrodes and a source of information and a method of controlling the record electrodes in the electrographic recording or printing device.
2. Description of Prior Art
Many prior art electrographic recording or printing devices are known which employ coincident current drive of record electrodes in order to reduce the necessary number of switching circuits operatively associated with the respective record electrodes. As one example, an electrographic type page printer described in U.S. Pat. No. 2,955,894 comprises a plurality of similar pin-shaped stationary record electrodes having the discharge areas thereof in surface alignment, anvil electrodes having positions and similarly spaced from the discharge areas to define a gap therebetween for the reception of a record medium and means for establishing an electric field by a difference in potential exceeding a threshold value when both of the record and anvil electrodes are selected. Although the necessary number of high-voltage switching elements for electrode selection is advantageously reduced, a severe disadvantage of this approach is a much higher accuracy of relative alignments between the record and anvil electrodes required for obtaining a good quality reproduction.
Another form of electrographic recording in the prior art involves first and second sources of voltage switchable between first and second voltage levels and first and second impedance elements interposed between a record electrode and the first and second sources, such a technique is disclosed in U.S. Pat. No. 3,483,566. However, these sources of voltages should both provide a voltage higher than the threshold value and therefore switching elements of high breakdown voltage are required.